INTRODUCTION: Health professionals emphasize the importance of breastfeeding in the development of children up to 6-months of age. It is known that short chain volatile fatty acids (SCVFAs) are a byproduct of nutrient fermentation by gut microbiome. These SCVFAs interact with the gut/brain axis and are known to influence infant development. Therefore, a reflection of maternal gut microbiome could likely be found in breastmilk (BM) due to diffusion of SCVFAs across the gut wall into the blood. Previous research in our laboratory has shown differences in the SCVFA fecal fermentation profile between individuals with normal (N) versus overweight/obese (OWOB) body mass index (BMI). Therefore, our research question is: Is there a difference in the relative amount and diversity of SCVFAs in the BM of N compared to OWOB women? We hypothesized that women of N will have a more diverse SCVFA profile than OWOB women in their BM. METHODS: BM samples (200 ml) were collected from 44 women (22 N (BMI 22.0) and 22 OWOB (BMI 33.7) p2 while OWOB participants had a pre-gravid BMI of greater than 25.0 kg/m2. A 300 mg aliquot of lyophilized BM was placed in a separatory funnel with 5 ml of hexane and 5 ml of volatile fatty acid solution (VFA, (oxalic acid (0.1M/L), sodium azide (40mM/L))). The funnel was rocked back and forth 50 times and placed on a ring stand to rest for 10 minutes. The bottom phase of the solution was collected and freeze-dried. Five hundred µL of VFA solution was added to the samples to resuspend, centrifuged (4,000 x g) for 20 minutes, the supernatant was removed and transferred to a microcentrifuge tube then centrifuged (12,000 x g) for 15 minutes and decanted. Three hundred µL of supernatant was transferred to autoinjector vials fitted with a 350 µL insert and analyzed for SCVFAs via gas chromatography (GC) (Shimadzu) using a Phenomenex ZB-Wax Plus glass capillary column. RESULTS: SCVFAs acetate, propionate, isobutyrate, isovalerate and caproate were not different (p>0.10), while valerate (p< 0.02), isocaproate (pCONCLUSION:To our knowledge, this is the first time that SCVFAs have been quantified in the milk of lactating women using GC with an FID detector. This data supports the argument that the pre-gravid BMI of a mother can correlate to the SCVFA profile of her BM. It is unknown if the concentration observed in the mother’s BM in this study has an influence on the neonate’s gut/brain axis and neurological signals, however, we have demonstrated that the SCVFA profile is more diverse in the N BMI mother. Further research is warranted on the influence of maternal BM SCVFA composition on the growth and neurological development of her infant.

INTRODUCTION: Health professionals emphasize the importance of breastfeeding in the development of children up to 6-months of age. It is known that short chain volatile fatty acids (SCVFAs) are a byproduct of nutrient fermentation by gut microbiome. These SCVFAs interact with the gut/brain axis and are known to influence infant development. Therefore, a reflection of maternal gut microbiome could likely be found in breastmilk (BM) due to diffusion of SCVFAs across the gut wall into the blood. Previous research in our laboratory has shown differences in the SCVFA fecal fermentation profile between individuals with normal (N) versus overweight/obese (OWOB) body mass index (BMI). Therefore, our research question is: Is there a difference in the relative amount and diversity of SCVFAs in the BM of N compared to OWOB women? We hypothesized that women of N will have a more diverse SCVFA profile than OWOB women in their BM. BM samples (200 ml) were collected from 44 women (22 N (BMI 22.0) and 22 OWOB (BMI 33.7) p2 while OWOB participants had a pre-gravid BMI of greater than 25.0 kg/m2. To our knowledge, this is the first time that SCVFAs have been quantified in the milk of lactating women using GC with an FID detector. This data supports the argument that the pre-gravid BMI of a mother can correlate to the SCVFA profile of her BM. It is unknown if the concentration observed in the mother’s BM in this study has an influence on the neonate’s gut/brain axis and neurological signals, however, we have demonstrated that the SCVFA profile is more diverse in the N BMI mother. Further research is warranted on the influence of maternal BM SCVFA composition on the growth and neurological development of her infant.